The installation of a circuit card is a convenient way of adding additional features to an electronic system. Examples of various types of circuit cards available for installation in computers are fax/modem cards, video cards, graphics accelerator cards, sound cards, and network interface cards, to name a few.
Many of today's computer systems are pre-configured with one or more circuit cards pre-installed by the manufacturer. A circuit card is typically installed into a computer system by removing the computer cover from the computer chassis, selecting an available and appropriate circuit card connector on the computer motherboard, lining up an outer edge of the circuit card with a chassis bracket slot, and lining up an inner edge of the circuit card with a circuit card receiving channel, also known as a card guide, sliding the edges of the circuit card down the respective chassis bracket slot and receiving channel, and inserting a connector of the circuit card into the motherboard connector.
The outer edge of the circuit card, positioned typically at the backside of the computer chassis, has a bracket screw assembly for securing the outer edge of the circuit card to the chassis bracket slot portion of the computer chassis. The inner edge is slid into the receiving channel and remains unsecured. Once the outer edge is screwed into place, the computer cover is replaced.
These computer systems are then shipped from the computer manufacturer to various recipients such as retailers, or directly to consumers. It has become apparent that these computers experience quite a bit of shock and vibration while in transit, since computer manufacturers receive complaints of inoperative or improperly functioning computers from the end users. It turns out that the pre-installed circuit cards were being jarred loose from the motherboard connectors. The vibration, or sudden jarring shock, causes the unsecured inner edge of the circuit card to slide back up the circuit card receiving channel. Since the outer edge is secured, the circuit card pivots about the bracket screw assembly, and a portion of the connector loses contact with the motherboard connector.
Sometimes, the solution to this problem is as easy as opening up the computer cover and ensuring that the connector is pressed firmly back into the motherboard connector. Other times, the pivoting of the circuit card out of the motherboard connector and up the circuit card receiving channel causes damage to one or more of the internal components, thereby requiring more involved repairs.
In an attempt to mitigate this problem, computer manufacturers started placing a foam strip, a piece of plastic, or a piece of metal on the inside of the computer cover. The idea behind this is that when the cover is replaced and secured to the chassis, the foam strip placed on the cover, or other material being used, comes into firm contact with the upper edge of the circuit card, thereby exerting a retaining force on the circuit card in the direction of the motherboard. With foam strips, the measurements did not have to be as accurate as with plastic or metal fillers since the foam strips would compress to accommodate the upper edges of the circuit cards.
This appeared to mitigate the problem of connectors jarring loose from the motherboard connectors, but the solution to that problem created problems of its own.
For example, many of the circuit cards being pre-installed by the computer manufacturers are manufactured by third party card manufacturers. Thus, there are no standard layouts for these boards. Many boards place various cable connectors on an upper edge of the circuit cards. In order to prevent damage or interference to these cables, the foam strips have to be cut so as to not run over these cable connectors.
Furthermore, these circuit cards typically come in two heights, the height being defined from the upper edge of the circuit card to the connector on the lower edge. Since computer systems are often custom configured, the location of these boards of various height are not always the same. Again, this requires that each individual computer system be custom fit with a foam strip according to the configuration of that particular system. The custom configuration of foam strips for placement on the computer cover is a labor intensive process which adds to the time and cost of manufacturing the computer systems.
Finally, with the passage of time, or with the constant insertion and extraction of various circuit cards, the foam strips start to break apart into little pieces which may cause interference with an internal fan, or various other internal components.
It should be noted that the problem of circuit cards jarring loose is a problem which faces individual computer owners as well as computer manufacturers. Some computer owners operate their computers in a mobile environment which can exert vibration and jarring shocks similar to that experienced by a computer being transported for delivery. In addition, consumers will often ship their computers during a move, or for repairs. Again, in such a situation, the circuit cards are exposed to vibrations and jarring shocks which tend to jar loose the connectors of the circuit cards from the motherboard connectors.
Therefore, a better solution is needed for securing and retaining a circuit card in the motherboard connector such that any vibration or jarring shocks resulting from shipping, or operation in a mobile environment, will not cause a circuit card to jar loose from the motherboard connector.
Furthermore, a better solution is needed which will minimize the amount of time spent in securing and retaining these circuit cards by creating a design which will be compatible with most of the standard circuit card configurations, regardless of where the upper edge cable connectors are placed, and ensuring that the solution does not create any by-products which could interfere with other internal components.